U.S. airlines are courting shoulder season travelers by slashing fares on fall flights to as little as $34 each way. Carriers including AirTran, Virgin America, Frontier and American have announced significant fare reductions for domestic routes (plus some flights to Mexico and the Caribbean). But buyer beware: Restrictions — from baggage fees to blackout dates — can make an airfare deal, well, not so much of a deal.

How do you get the best price for your particular itinerary? It all depends on which cities you’re flying between, what your travel dates are and how many bags you want to check — so it’s important to search for your itinerary on multiple airline Web sites to see where you can find the cheapest rates (and check out our airline baggage fees roundup for info on different airlines’ checked bag charges). To give you an idea of which bargain may be best for you, here’s a brief rundown of what’s on offer:

AirTran Airways
This systemwide sale includes hundreds of discounted routes with fares starting at $54 each way before taxes. Available travel dates are broad: fly through the end of January on any day of the week except Fridays and Sundays.

What’s the Catch? There are some holiday blackout dates, and your first checked bag costs $20.

Virgin America
Travelers heading to California or Las Vegas can book flights for as little as $39 each way before taxes. This includes noteworthy coast-to-coast fares like Washington D.C. to Los Angeles for $109 each way.

What’s the Catch? Travel dates are limited. You’ll only get the very cheapest fares by traveling between September 14 and October 6 on select days of the week. Plus, each checked bag costs $25 each way.

Frontier
Frontier’s offerings include discounted flights to cities throughout California, the Midwest, the Rockies and other U.S. regions, starting at $34 each way before taxes. Travel is good through December 15.

What’s the Catch? Flights are not available on Fridays or Sundays, and a $20 fee applies to each of your first two pieces of checked luggage.

American Airlines
Fares start at $59 each way plus taxes, and this deal encompasses a wide range of travel dates. You can fly through the end of January.

What’s the Catch? Look out for numerous holiday blackout dates, including seven blackout days in November. You can only fly on Mondays, Tuesdays, Wednesdays, Thursdays and Saturdays. Keep in mind that American charges $25 each way for your first checked bag and $35 each way for your second checked bag.

To see more cheap flights, check out our Airfare Deals. Which deal do you think is the best? Will you be booking fall travel with any of these airlines? Post your comments below!